My site http://www.gldhc.com is hosted by Google, but the my domain is registered with Dream Host. Last night (9/21/10) the domain expired. It was suppose to auto renew. Bare in mind the site was working fine when I went to bed last night. This morning the site is down. I have made no changes to the domain settings at Dream host or my google site. It should have automatically kept working.

Yep, it looks like there are no DNS records. Since it's expired, it's quite possible that DreamHost knows to stop serving DNS for that domain. You should be able to jump into Registrations and click on a Renew Now link (and pay for the renewal). Hopefully that'll wake it up.